<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>demo 2-22</title>
	</head>
	<body>
	</body>
	<script>
		function move({x = 0,y = 0} = {}){
			return[x,y];
		}
		console.log(move({x:3,y:8}));
		console.log(move({x:3}));
		console.log(move({}));
		console.log(move());
	</script>
</html>